A. Field of the Invention
The invention is a sensor for use in hot water heating system furnaces. The sensor detects both the temperature of water inside the furnace and also whether water is present in the furnace at the sensor. The combination sensor of the Invention may be used in any system where monitoring of the presence of water and also the temperature of the water is needed.
B. Statement of the Related Art
Hydronic heating systems utilize heated water or steam flowing through pipes from a central furnace to supply building heat. The firing of the furnace is only needed if the control system requires building heat and if the temperature of the water in the furnace is below a target temperature. If a water temperature sensor malfunctions, the sensor may mislead the control system into providing no building heat or may mislead the control system into overheating and damaging the furnace.
Hydronic furnaces depend upon the water in the furnace to absorb and distribute heat from the firing of the furnace. A leak in the hydronic heating system may cause the water level in the furnace to fall, resulting in a low-water condition. If a hydronic furnace experiences an undetected low water condition, temperature sensors may not function properly to control the temperature within the furnace, which may cause local overheating and damage to the furnace.
The prior art does not teach the sensor of the Invention.